Electromagnetic relay having a unitary structure forming respectively the core and the yoke



Dec. 2, 1969 J, FISCHER ET AL 3,4

ELECTROMAGNETIC RELAY HAVING A UNITARY STRUCTURE FORMING RESPECTIVELY THE CORE AND THE YOKE Filed Aug. 6, 1963 2 Sheets-Sheet 1.

Fig.1

J- FISCHER ET AL Dec. 2, 1969 3,482,193

ELECTROMAGNETIC RELAY HAVING A UNITARY STRUCTURE FORMING RIESPECTIVELY THE CORE AND THE YOKE 2 Sheets-Sheet 2 Filed Aug. 6, 1963 l FD United States Patent ELECTROMAGNETIC RELAY HAVING A UNI- TARY STRUCTURE FORMING RESPECTIVELY THE CORE AND THE YOKE N Josef Fischer, Herbert Krautwald, and Wolfgang Hubner,

Munich, Germany, assignors to Siemens Aktiengesellschaft, Munich, Germany, a corporation of Germany Filed Aug. 6, 1963, Ser. No. 300,229 Claims priority, applicatitan GGermany, Aug. 9, 1962,

The portion of the term of the patent subsequent to Apr 2, 1982, has been disclaimed and dedicated to the Public Int. Cl. H01f 7/08, 7/13, 3/00 U.S. Cl. 335220 3 Claims The invention disclosed herein is concerned with an electromagnetic relay having in the interest of rational fabrication only a relatively small number of individual parts, including a unitary structure forming respectively the core and the yoke, with the armature journalled on the yoke.

Previously known relays have a magnetic circuit formed by the armature, the yoke and the core which is provided with pole pieces, the core being constructed of crosssectionally round or flat material. The core is in most cases connected with the yoke by threaded means or by riveting or welding. Since the corresponding connection is not homogeneous, there appear magnetic transition resistances which affect the efficiency of the relay. The assembly of the core with the yoke, each of which must be individually constructed, requires an expenditure of labor which must also be considered as items of importance affecting the economy of production.

The object underlying the present invention is to provide a structure which overcomes the above-indicated drawbacks and which reduces the expenditure of labor so as to facilitate a mechanized production of relays. The magnetic circuit shall be dimensioned at an optimum, so as to avoid reaching the saturation limit in the operation of a relay and to likewise avoid over-dimensioning which would result in waste of highgrade material. The lastnoted aspect is particularly important in the case of mass production wherein even small savings on material add up to considerable totals. It is, moreover, desirable to provide for mechanized production a structure requiring as few machining operations as possible, so as to avoid expenditure of labor and material connected therewith.

The invention satisfies the above-indicated requirements by the provision of a relay with hinged armature, which is adapted for rational production, the magnetic system of such relay, including a core and a yoke, being made of a single U-shaped part having legs which are of identical length, and the approximately identical rectangular cross-section of the cores and the yoke being diiferent as to the dimensions thereof.

The use, according to the invention, of a single structural part for the yoke and the core, which required in previously known comparable relays, two individual parts, results in the further advantage of avoiding any overdimensioning with respect to the yoke and the core. It must be considered in this connection that the operatively effective cross-section of the core is, despite dilferences in the dimensions, which are provided for structural reasons, identical with that of the yoke; and there will therefore not occur any crowding of the lines of force, in the operation of the magnetic system according to the invention, since there is always the same iron, i.e., magnetic cross-section available for the energizing flux.

The thickness of the core profile, as compared to the yoke profile, is in a preferred embodiment of the invention selected in a ratio of about 2:1. Accordingly, as in customary structures, the yoke can have a width which r: ICC

corresponds to the outer dimensions of the energizing coil which is slipped on the core, the latter being only half as wide as the yoke. Despite this difference in Width obtaining between the core and the yoke, there will not result an iron, i.e. magnetic path, even upon optimum utilization of the magnetic material, along which a magnetic saturation could occur due to crowding of the lines of force.

In the relay according to the invention, the armature is journalled at the end of the yoke, with the aid of a stamping provided on the armature, thus further reducing the number of parts required for the production. It is in connection with the jounalling of the armature for constructional reasons particularly advantageous to provide an armature-restoring spring having two arms extending in the direction of the yoke, with the ends of said arms bent at right angles for cooperative engagement with holding ears formed on the yoke incident to the stamping or punching thereof.

The armature is thus held merely by the restoring spring and can be removed at any time by withdrawing the ends of the spring arms from the holding ears. Upon removing the armature in this manner, the energizing coil can be for any desired reason, for example, for the exchange thereof, slipped off from the yoke without the use of any particular auxiliary device. The fact that the mounting and removal of the energizing coil, the armature and the restoring spring, can be effected without the use of any adjusting device and without the use of special tools, constitutes a particular advantage.

According to another feature of the invention, the structural parts forming respectively the core and the yoke are punched from a rolled iron strip having portions of different thickness, and thereafter worked in successive production phases, including the bending thereof in U-shape webs remaining upon subsequent separation of the parts, serving as cars for holding the cover cap for the respective relay in which the parts are used. These webs must serve for holding the individual structural parts together during the production process so as to enable appropriate working of the parts in the course of the mechanized production process. The use of the webs remaining upon subsequent separation of the parts, as holding ears, constitutes a particularly advantageous feature since it eliminates the necessity of providing separate holding means for the cover cap.

Further details of the invention will appear in the course of the description of an embodiment which is rendered below with reference to the accompanying drawings, wherein FIG. 1 shows an embodiment of the electromagnetic relay with hinged armature, according to the invention;

FIGURE 2a is a side elevational of the journal structure between the armature and the yoke, with a portion broken away to show the details thereof;

FIGURE 2b is a sectional view taken approximately along the line 2b2b of FIGURE 241;

FIGURE '20 is a sectional view taken approximately along the line 2c2c of FIGURE 2a;

FIG. 3 indicates phases in the production of the unitary core and the yoke parts from a profiled strip; and

FIGURE 4 is a sectional view taken along the line 44 of FIGURE 3.

The electromagnetic relay shown in FIG. 1 comprises the core 1 and the yoke 2, forming elements of a magnetic system, such elements being represented by the legs of a single U-shaped structural part, which legs are of identical length. The initial material for this structural part has a rolled profile. In order to obtain in the mag netic circuit identical iron cross-sections for the energizing flux, the narrower core 1 is made with a thickness s1 while the wider yoke 2 is made with the thickness s2. These differences in thickness can be readily obtained by the selected profile of the rolled blank, without having to use any machining operations. Since the legs of the U-shaped structural part which form the yoke and the core, are substantially equally long, they can be milled or ground to accurate length in a common operation or compressed to accurate length by using appropriate holding means.

As shown in FIGS. 2a to 20, the armature 5 is journaHed at the end of the yoke 2 with the aid of an elongated projections of stamping 5a provided on the armature. This stamping 5a forms a guide for the armature 5 lying upon the end of the yoke 2, a restoring spring 6 holding the armature 5 in its normal or released position. A rectangular protuberance 50, adapted for entry into a recess 21; formed in the yoke 2, may be provided to secure the armature laterally of the yoke.

In its attracted position, the armature 5 will lie com pletely planar upon the yoke 2 and the core 1, which functions as a pole surface of the magnetic system. The armature 5 is held by the spring 6, provided with two legs or arms 6a, which are engaged by holding ears 2a formed on the yoke 2 the arms 6a passing through slots 5d in the armature. This mode of fastening the armature enables removal thereof and subsequent removal of the energizing coil 3 and coil frames 3a, on which it may be mounted, from the core 1.

The armature 5 is provided with an arm 8 which extends therefrom and carries an actuating member 7 for controlling the operation of the relay contacts. The armature arm 8 is provided with a reduced section 8a in order to enable adjustment of the armature stroke. The contact arrangement comprises a contact set including stationary contact elemens 12 for cooperation with a contact spring 13 which is controlled by the actuating member 7. A plurality of contact sets may be provided if desired. The contact combination shown in the drawing provides for a break-before-make action. It is understood, of course, that different contact combinations may be used. The connections to the stationary contact elements such as elements 12, and to the contact springs such as spring 13, as well as the connections to the energizing coil 3, are established by means of terminal contact members 14.

FIG. 3 shows in schematic manner phases in the production of the unitary core and yoke elements from a profiled strip having portions of different thickness as shown in the sectional view 4--4. The punching of the blank forming the portions 1 and 2, with holes 15 formed therein, is effected in the production phase I. The upper portion forms after the bending operation, which is effected in the production phase II, the core 1, while the lower portion will form the yoke 2. The yoke portion 2 is provided with the previously mentioned ears 2a which are formed thereon during the stamping or punching operation, such ears serving for holding the arms 6a of the armature spring 6. The holes 15 which are, during the production phase V provided with threads, serve for fastening the magnetic system on the insulating plate 10, with the aid of fastening means 9, shown in FIG. 1. A terminal 9a for a ground connection may be provided at this point. FIG. 3 also shows the webs 4 which remain upon separating a completed U-shaped part, forming the core 1 and the yoke 2, at the conclusion of the production thereof, such webs serving as holding means for the cover cap 11 shown in FIG. 1.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

We claim:

1. An electromagnetic relay comprising:

a single U-shaped part including two fiat parallel legs,

a core leg and a yoke leg, joined by a base section, said legs having substantially identical magnetic cross sections and said part being magnetically homogeneous from the free end of said core leg to the free end of said yoke leg wherein said core leg has a flat cross-sectional thickness of about 2:1 with respect to said yoke leg, said yoke leg has a flat cross-sectional width of about 2:1 with respect to said core leg, and said part includes only two bends to form the coreyoke structure, said two bends being located in said base section immediately adjacent said core and yoke legs, respectively,

webs located on said U-shaped member between said bends and disposed on laterally opposite sides thereof and adapted to serve as ears for holding a cover cap for the respective relays in which the parts are used, an energizing coil disposed on said core leg;

an armature journalled at the free end of said yoke leg; and

spring means engaging said yoke leg and said armature to urge said armature toward its restored condition.

2. The electromagnetic relay according to claim 1 wherein said armature includes means thereon forming a first recess and at least one tab protruding into said recess, and wherein said yoke leg includes means on the free end thereof forming a second recess, said free end of said yoke leg being disposed in said first recess with said tab disposed in said second recess forming a journal for said armature.

3. The electromagnetic relay according to claim 2, wherein said yoke leg further includes a pair of tabs disposed on laterally opposite sides thereof and wherein said spring means includes first and second resilient legs each having an aperture therein and a third leg, the first and second resilient legs being disposed to straddle said yoke leg with the apertures thereof receiving said tabs of said yoke leg in releaseable engagement, and said third leg bearing on said armature to urge said armature toward its restored condition.

References Cited UNITED STATES PATENTS 2,913,548 11/1959 Martin 335-276 2,917,600 12/ 1959 Smith 335-281 XR 3,117,255 1/1964 Peterson 335-276 XR FOREIGN PATENTS 1,108,457 8/1955 France.

VOLODYMYR Y. MAYEWSKY, Primary Examiner DEWI'IT M. MORGAN, Assistant Examiner U.S. C1. X.R. 335-270, 3274, 281 

1. AN ELECTROMAGNETIC RELAY COMPRISING: A SINGLE U-SHAPED PART INCLUDING TWO FLAT PARALLEL LEGS, A CORE LEG AND A YOKE LEG, JOINED BY A BASE SECTION, SAID LEGS HAVING SUBSTANTIALLY IDENTICAL MAGNETIC CROSS SECTIONS AND SAID PART BEING MAGNETICALLY HOMOGENEOUS FROM THE FREE END OF SAID CORE LEG TO THE FREE END OF SAID YOKE LEG WHEREIN SAID CORE LEG HAS A FLAT CROSS-SECTIONAL THICKNESS OF ABOUT 2:1 WITH RESPECT TO SAID YOKE LEG, SAID YOKE LEG HAS A FLAT CROSS-SECTIONAL WIDTH OF ABOUT 2:1 WITH RESPECT TO SAID CORE LEG, AND SAID PART INCLUDES ONLY TWO BENDS TO FORM THE COREYOKE STRUCTURE, SAID TWO BENDS BEING LOCATED IN SAID BASE SECTION IMMEDIATELY ADJACENT SAID CORE AND YOKE LEGS, RESPECTIVELY, WEBS LOCATED ON SAID U-SHAPED MEMBER BETWEEN SAID BENDS AND DISPOSED ON LATERALLY OPPOSITE SIDES THEREOF AND ADAPTED TO SERVE AS EARS FOR HOLDING A COVER CAP FOR THE RESPECTIVE RELAYS IN WHICH THE PARTS ARE USED, AN ENERGIZING COIL DISPOSED ON SAID CORE LEG; AN ARMATURE JOURNALLED AT THE FREE END OF SAID YOKE LEG; AND SPRING MEANS ENGAGING SAID YOKE LEG AND SAID ARMATURE TO URGE SAID ARMATURE TOWARD ITS RESTORED CONDITION. 